Process for obtaining nitrogen from the air



Jan. 8 1924. 1,480,291

w. NELSON PROCESS FOR OBTAINING NITROGEN FROM THE AIR Filed July 15.1923 m/xm BENTON/TE CARBON Patented Jan. 8, 1924.

UNITED rice.

WILBUR ARMISTEAD NELSON, OF NASHVILLE, TENNESSEE.

PROCESS FOR OB'IAiNING NITROGEN FROM THE AIR.

Application filed July 13, 1923. Serial Zia 651,258.

of my copcnding application Serial Number- 601,291, filed November 16,1922, which has matured into Letters Patent No. 1,465,310, August 21,1923, for a process for obtaining nitrogen from the air. It is essentialto the successful operation of the processes constituting the subjectmatter of both of these applications that moisture be supplied duringthe working of the process. This moisture may be supplied either byintroducing moist air or by employing a bentonitic clay or othermoisturebearing aluminum silicate. The line of division between thisapplication and my copending application aforesaid is that the saidcopending application has been restricted to that form of the inventionwherein the moisture is supplied through the current of air. Thisapplication will be devoted to that form of the invention wherein themoisture is supplied through the use of a moisture-bearing aluminumsilicate. In addition, the present invention and application defines awider range of temperatures than those specified in myprecedingapplieation, since I have found by experiments that thetemperatures actually employed by me range somewhat lower than Idisclosed in myv said copending application.

This invention contemplates passing a current of air, which may bepreheated, through a closed furnace which contains carbon and a complexhydrous aluminum silicate in the form of a clay. Preferably the clay andcarbon are intimately mixed before being placed in the furnace. By meansof the furnace the. carbon and clay are heated to a point above that atwhich the-water of constitutionis driven ofi' and to the point whereammonia isformed. I find that temperatures as low as 460 0. yieldsatisfactorvresults and I contemplate'employing 10, to a flange 11 ofshell 5.

temperatures anywhere between 400 C. and 1200 C.

The air drawn through the furnace and the gases formed in it are thenpassed through a condenser which condenses the water vapor which hasabsorbed the ammonia with the result that ammonium hydroxide isdelivered from the condenser.

I have practiced the foregoing invention in the following way: A mixtureof bento-J nite and gas carbon reduced 'to a plastic form by theaddition of water was shaped to form balls or a cylindrical roll and insuch form was placed in an iron electric fur-.

nace and heated to 1000 C. Heated air was drawn throu'ghthe furnace fromthe beginning of the heating and until the tem perature hadreached themaximum pdint and the gases and air drawn from the furnacc were passedthrough a condenser. The water vapor driven off from the bentoniteabsorbed the HITIIIIOIIlE WlIlClI formed in appreciable amounts when thetemperature reached 460 C. and thereafter and the 0011- densation ofthese gases resulted in'a continuous yield of ammonium hydroxide afterthe temperature reach-ed approximately 460 C. and up to the point ofmaximum temperature employed.

In the accompanying drawing, I have diagramuiatically illustrated anapparatus by which the invention may be practiced.

In this drawing 5 designates the shell or body of a furnace having anelectric heating coil 6 wound externally thereon. This coil and shellare enclosed in a jacket 7 'of insulating material. A sleeve 8 fitssnugly within the shell and isprovided with a cap or head 9 adapted tobe secured by screws The charge of mixed bentonite and carbon .isindicated at. 12. An inlet pipe 13 delivers air, which is preferablypreheated, to the furnace and an outlet pipe 14 conducts this air andthe gases generated in the furnace to any suitable type of condenser 15.Preferably this is a conventional water cooled condenser. Any suitabletype of receptacle, indicated at 16,

may be disposed in position to receive the ammonium hydroxide from thecondenser. A suitable suction pipe, indicated at 17, in- .ducesa currentof the heated air through the apparatus.

The ben-tonite referred to and which I have found oflparticular utilityin the pracs.

tice of the invention described, is a clay .formed by the altering of abed of volcanic ash and has as its chief mineral constituentleverrierite. The mineral leverrierite swells 6 in water and breaksupinto a doughy mass.

Itiis distinctly crystalline and in plates. It is softfseetile andclay-like. Ithas an 'indexfiof refraction of def about 1.57,

birefringence of about 0.02, a very small 10 axial angle and isoptically negative in character. The acute bisectrlx 1S sensibly normalto the plates. These are the characteristic properties of leverrierlte.Quoted from an article? by E. S..Larsen and Edgar l5 1T. \Vherry,entitled, Lererrierite from Colorado}? in volume 7, No; 8, pages 208 to214 of the Journal of the Washington Academy of Science. I

While I prefer to use bentoniteit is to be understood that the inventionincludes u'ith- 1n=1ts purview the use of such other clays andcarbonaceous materials as may be found suitable for the purpose. Forexample, I

contemplate the use of powdered or granu- 'lar wood charcoal, powderedor granular coke or flake 01'1311101Pl101l5 graphite and I alsocontemplate employing bauxite, ball clay or kaolin or'any bcntonitieclay or aluminum silicate containing hydroscopic .water or water ofaconstitution, which can-- not be driven off at less than 200 C.

Having described my invention what'I claim is:

1.: The hereindescribed process which con 85:1s1sts of heating a mass ofmo1sture-bear1ng clay and carbon, passing-a current of air in contacttherewith thereby forming ammonia and condensing the water vapor whichabsorbs the ammonia whereby ammonium byw :droxide is recovered.

2. The herein described recess which consistsof heating amass omoisture-bearing bentonite and carbon to a temperature between 460 C.and1200 C, passing a cur- 5i rent of air in contact therewith therebysists of passing a current of air in contact. with a mass ofmoisture-boaring aluminunr; silicate and carbon heated to a temperaturewhere:ammonia is formed and condensing;

the water vapor a't'teiwit has absorbed the ammonia to thereby recoverammonium hy-L,

droxide 4. The herein described process which consists of heating a masscomposed of a bentonitic clay and a carlmnaccous material in Ge intimatemixture to approximately 4009 UL,

passing or-cr said mass a current of niiiiand condensing the water vaporto recover am-. monium hydroxide. i

o. The herein dcscrlbed process which eon-1: it sists oi heating a massof aluminum silicate;v

and carbonaceous material in the presence 01 p moisture and air toa-point at- \VlllCll lam monia 1s formed and condensing the water vaporwhich has absorbed the ammonia itoi'lo' 1 thereby recover ammoniumhydroxide,

G. The herein described process \Vl11cl1CQI1-',

sists of heating; a mass of bentonitic clay and carbonaceous material toa temperature 5 between 460 C. and 1200 C. in the pres-fies cnce ofmoistureand air whereby ammonia is forn'ied and condensing the watervapor v which has absorbed the ammonia to there-" v by recover ammonium.hydroxide 7 The herein described process \VlllOhCOIlfi 8051 sists of:heating a mass of bentonitie clay;

and a. carbonaceous material. in the presence": I of moisture and air toaipoint. :at which ant-1.-

monia is formed and condensing thewaterw vapor which has absorbedthe.ammoniaito: thereby recover the ammonium: hydroxides,

In testimony whereof :I hereunto affizumy signature.

WI'LBUR ARMISTEAD NELSON; l i

